The invention pertains to personnel-protective (blunt object impact and noise suppression) helmet shell construction, and in particular, to such a shell, and to a method of making the same, where inner and outer, load-bearing, semi-rigid structural layers in the shell are formed/fabricated by the process of vapor-suspension, material-spray deposition. Preferably employed for such a structural spray is a two-component, polyurea/polyurethane spray elastomer system, such as the component system known as HYDROTHANE made and sold by Hydroseal Polymers, Inc. of Riverside, Calif. The two components making up this product are isocyanate and polyol. We have discovered that this commercially available system, which is focusedly designed to create protective coatings over other objects, can itself be employed to form independent structural object per se. This discovery opens the door to the moldless creation of many different kinds of structural objects, such as the helmet shell structure which is particularly disclosed and illustrated herein.
This spray material, appropriately prepared for spraying as a particle vapor-suspension, includes particles having a strong bonding affinity for one another upon contact. Contacting particles conglomerate after landing with one another to form, progressively, a solid, semi-rigid, load-bearing structure. The xe2x80x9cexposedxe2x80x9d surface of this forming structure has an infinitely and subtlety selectable and controllable topography, dictated principally by how much material is sprayed, and how the forming spray is aimed and maneuvered, during the spraying procedure.
Proposed by the invention is a novel multilayer (especially three-layer), personnel-protective helmet shell construction wherein a central (or core) layer is formed of a suitable shock-absorbing (and also sound-deadening) soft, viscoelastic, microcellular foam layer, jacketed on its inner and outer surfaces by sprayed-formed, more rigid (semi-rigid) layers of a vapor-suspension, structural deposition plastic material. As will become apparent, the invention features a simple, quick, precise, inexpensive and reliably repeatable manufacturing practice which offers a number of significant functional advantages, and attractive fabrication economies, in relation to conventional, molded, helmet-shell practices. The resulting helmet shell offers robust, high-level load-distribution and blunt-object-impact cushioning performance, as well as noise suppression.